You probably remember the popular children's animated series "The Land Before Time", about a group of little dinosaur friends looking for the Great Valley after a major earthquake. In ancient times, natural disasters happened much more often than today, and at some point they put an end to the whole race of giant reptiles. This happened 66 million years ago, at the end of the Cretaceous period. It was then that dinosaurs, as well as sea reptiles and flying lizards, completely disappeared from the face of the Earth. But do you know what happened after they went extinct? If not, you've found the right place: today we will be looking into that.